1. Field of the Invention
This invention relates to a camera system of the kind permitting use of a motor drive device by mounting the device on a motor-incorporating camera.
2. Description of the Related Art
Many of the cameras provided these days are arranged to automatically perform not only film winding and rewinding but also a shutter charging action, etc. by using the driving force of a motor incorporated in the camera. The cameras of this kind are disclosed, for example, in U.S. Pat. No. 4,816,851, No. 4,616,913, No. 4,673,272, etc.. A preparatory operation for photographing can be greatly simplified by the motor-incorporating type camera which is capable of automatically performing the above-stated actions of varied kinds. The camera of this kind is favored by the users as it enables them to concentrate their attention on picture composition.
However, the relish and requirements of camera users are diverse. Therefore, it is hardly possible to satisfy all the requirements of the users with a single camera unit even by any of recent motor-incorporating type cameras. For example, some camera users prefer to have a smaller camera even at the expense of a high shutter speed. Some other users prefer to have a higher shutter speed even at the expense of a smaller size of the camera. Meanwhile, some users wish to have the camera arranged to permit selection of a film frame feeding speed from among varied speeds according to the purpose of use.
In order to meet the diverse requirements of the users, the motor-incorporating type camera is preferably arranged to permit a motor drive device to be mounted on the camera. However, the conventional motor-incorporating type camera is arranged in a manner unsuitable for mounting any additional motor drive device as the such cameras have been designed under a desire to have the motor drive device incorporated also in a manual operating type camera. Further, any attempt to have the conventional motor drive device mounted on the conventional motor-incorporating type camera would bring about the following problems (i) to (iii), which have prevented actual mounting of the conventional motor drive device on the conventional motor-incorporating type camera:
(i) If a motor drive device of the conventional type is mounted on the conventional motor-incorporating type camera, a power source and a related power transmission mechanism assembly must be arranged outside the camera in parallel with, and separately from, another power source and a related power transmission mechanism assembly which are arranged inside the camera. When the motor drive device is mounted, the power source and the power transmission mechanism would be left idle to cause the total weight of the camera to include a dead weight, which would unnecessarily be carried by the camera operator.
(ii) Generally, a power transmission system arranged between a motor and a load includes a reduction gear train. If the conventional motor drive device is mounted on the conventional motor-incorporating type camera in the same manner as mounting it on the conventional manual operating type camera, the driving power transmission system of the motor drive device would be connected to the internal power transmission system of the camera at a point close to the load of the internal power transmission system. Under such a condition, the reduction gear train disposed inside the camera would be driven by the motor disposed within the motor drive device. As a result, an extremely great load would be imposed on the motor. This would require the motor drive device to have a battery of a large capacity disposed within the device . and also to have the power transmission mechanism strong enough to be capable of transmitting a large torque. To meet these requirements, the motor drive device would become large, heavy and expensive.
(iii) With the motor drive device mounted on the motor-incorporating type camera, if the power transmission system of the motor drive device directly engages a load, such as a film winding mechanism, a shutter charging mechanism or the like disposed within the camera, the load on the motor disposed within the motor drive device could be minimized to prevent the size, weight and cost of the motor drive device from increasing. In actuality, however, the load within the camera, such as the film winding or shutter charging mechanism or the like, is disposed away from a part mechanically connecting the power transmission system of the motor drive device to that of the camera. The power transmission system of the motor drive device thus cannot be connected directly to the load disposed within the camera. Further, any design to have the power transmission system of the motor drive device connected directly to the load within the camera would result in extremely complex structural arrangement of the two power transmission systems.